JPS59186602A - Gas separation membrane - Google Patents

Abstract

PURPOSE:To obtain a gas separation membrane by using a polymeric material obtained by adding a silicon compd. having a reactive group to an ethylenic polymer having an unsaturated group, or further treating with a cross-linking agent. CONSTITUTION:The gas separation membrane contains >=1mol constitutional unit as represented in the formula, and obtained by adding a hydrolyzable silicon compd. such as hydrosilanes having hydrogen on silicon or cyanosilanes having a cyanic group, at >=30 deg.C with or without a catalyst, to an ethylenic polymer such as 1,2-polybutadiene, linear poyvinylbenzene, or a copolymer of styrene and divinylbenzene, and forming the obtained compd. into a membrane. The membrane, obtained with the above-mentioned method, and further treated with a cross-linking agent such as polycyclohexane to increase the permeability for the gas separation, can be used as the membrane or formed into the membrane on a porous membrane in the same way as the above-mentioned membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to gaseous membranes. Specifically, the present invention relates to a gas separation membrane in which a silicon compound having a reactive group is added to an ethylene polymer having an unsaturated group, and the mechanical strength and gas separation performance of the membrane are improved by crosslinking the membrane as it is or by using a crosslinking agent.

Gas content - Membranes require a high gas separation rate and high permeation velocity. In order to satisfy such performance, it is necessary to make the membrane layer having substantial separation ability as thin as possible. If the seven rollers try to reduce the film thickness too much, defects will eventually occur and separation ability will be lost. Therefore, in order to reduce the film thickness, it is possible to increase the mechanical strength of the film material or to maintain and strengthen it in a porous layer. Here, various methods have been devised to strengthen retention in the porous layer. For example, on top of a porous layer.

A method of overlapping separately formed thin films, a method of forming an anisotropic film in which the epidermis layer and a porous layer coexist, a method of directly polymerizing monomers on the porous pleura by various methods, etc. to form a thin film. There is a method of forming a thin film by evaporating the solvent in a sample of a polymer solution.

The present inventors have intensively studied molecular materials suitable for the above method, added a silicon compound having a reactive group to an ethylene polymer having an unsaturated oro group, and used the method as a cross-linking agent. The present invention was based on the discovery that by crosslinking using a methane compound, the strength of the resulting membrane can be increased and a membrane with high separation performance can be obtained. That is, the gist of the present invention is an abbreviated structural unit represented by the following general formula (1) (in the formula, an integer from n to 0 to 5, R1゜R2 and R3, a hydrogen atom, a halogen atom, an alkyl group) -) represents a phenyl group and may be the same or different from each other. ) is present in a gas separation membrane whose main component is polyester containing 1 mol% or more.

To explain the present invention in detail, the forefoot general formula (1)
- The ethylene-based monomer containing 1 mol or more of the structural unit shown (hereinafter referred to as component A) may be in liquid or solid form, and contains 7 mol% of the structural unit of the forefoot general formula (1). As mentioned above, it is desirable that the content is preferably 17-570 mol% or more and that it is soluble in organic solvents. Here, if the proportion of the structural unit (1) is less than 7 mol%, the amount of the silicon compound added below will be small, and therefore the degree of subsequent crosslinking effect will be small, resulting in a decrease in mechanical strength, which is disadvantageous. Furthermore, a significant decrease in gas separation performance also occurs. Specific examples of component A include /, 2-polybutadiene, linear polydivinylbenzene, styrene-divinylbenzene copolymer, etc., but of course these Kff1E are not defined.

The silicon compound that loses the hydrolyzable atom or atomic group (hereinafter referred to as component B, l-) must be able to undergo an addition reaction with component A, and is therefore generally a hydrosilane containing hydrogen on silicon or a Examples include cyanosilanes having a d-cyano group. Such silicon compounds can undergo hydrosilylation or cyanosilylation reaction by heating at 30°C or higher without using a catalyst, or by using a metal such as platinum, rhodium, cobalt, or a catalyst such as peroxide. Can be added to unsaturated bonds in components. Furthermore, it is necessary that an atom or atomic group that can be hydrolyzed exists on the Ki component B, and such atoms or atomic groups include hydroxyl group, amino group, alkoxy group, acyloxy group, mercapto group, acyl group, Examples include a cyano group, an epoxy group, a hydrogen atom, and a halogen atom. The silicon compound of component B must have the above-mentioned functional group, but it may also have one or more chain or cyclic polysilane τ, or it may have a siloxane bond, or it may contain several types of silicon atoms. It may be a mixture. However, it is preferable that component B is soluble in a suitable organic solvent and has a molecular weight of 100θ or less.

Specific examples of component B include halogenated silicon compounds such as dimethylchlorosilane, dichlorotetramethylsilane, trichlorosilane, tribromosilane, tetramethylchlorodisilane, and tetrachlorocyclotetrasiloxane, triethoxysilane, trimethoxysilane, and dimethylethoxysilane. Alkoxysilanes such as , methylethoxysilane, tetramethoxydisilane, enyldimethoxysilane, diphenylmethoxycyanosilane, bisdimethylaminomethylsilane, dimethylaminomethylchlorosilane, dimethylaminodimethylsilane, aminosilane, acetoxydimethylsilane, methyldiacetoxysilane , acetoxysilanes such as fer≧rumethylacetoxysilane, mercapsilanes such as dimethylsilylmethylmercaptan and diethylsilylmethylmercaptan, and acylsilanes such as dimethylacylsilanes and diethylacylsilanes, but these are / It can be used as a mixture for glazing or more.

The addition reaction between component A and component B can be carried out at a temperature of 0° C. or higher, preferably tL<3θ to 300° C., in an undissolved solution or in a suitable organic solvent.

d, hexane,
Heflin, aliphatic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene, tolueno, xylene, halogenated hydrocarbons such as chloroform, carbon tetrachloride, chlorobenzene, dichlorobenzene, fromoform, etc.
A/: Ethers such as r---r, tetrahydrofuran, and dibutyl ether can be mentioned. In addition, 0.5 mole or more, preferably -1 = L (preferably -7 to 700 moles), is used for the unsaturated 1st bond of component B and component A, and the reaction is carried out in an inert gas. It is preferable to do so.

This is because hydroxyl groups are introduced onto silicon by moisture in the air, and then condensed with other amino groups, nitrogen, hydroxyl, acyl, mercapto-containing silicon substituents or unreacted silicon compounds. 25) et al., in which the crosslinking reaction proceeds.

The adduct of the silicon compound obtained as described above is sweetened with unreacted component B, and after removing volatile components such as unreacted component B and solvent, it is dissolved in a suitable organic solution IJI.
After dissolving K, it can be used for film formation. Film formation involves the reaction γ, the force of flowing the clear liquid of the compound onto a glass plate vs. There are ways to erase it, but the method is not limited. However, whichever method is used, in order to promote crosslinking of the reaction product and improve membrane strength and gas separation performance, the temperature should be 0°C or higher, preferably room temperature to /θ0°C.
, 7 hours or more, preferably 7 to . It is preferable to leave it in the air for 29 hours or avoid contact with water vapor. θ~300℃
It can also be heat treated at a temperature of .

The membrane obtained by the above method has gas separation ability in the first method, but in order to further improve the gas see-through performance, the membrane material is treated with a crosslinking agent and then formed into a membrane. Good too. Such treatment allows the introduction of materials, such as polysiloxanes, which are generally known to have high gas permeability into the membrane material. For example, in the addition reaction product of component B to component A, the reactive group present on component B or its hydrolysis 11 Jr.
A polysiloxane that cures one or more functional groups capable of addition or condensation reaction with the hydroxyl group obtained in step 4 is added to cause a crosslinking reaction, thereby producing a forest material for a gas separation membrane. The structure and molecular weight of such polysiloxanes are not limited.
Examples of such polysiloxanes include α,ω-dihydroxyboridimethylsiloxane and α.

α, ω to ω-dihydroxypolymethylphenylsiloxa
- Linear polysiloxanes such as diaminopolydimethylsiloxane, α,ω-diglycidylboridimethylsiloxane, α,ω-diacetoxypolydimethylsiloxane, α,ω-dimethoxypolydimethylsiloxane, cyclopolymethylmethoxysiloxane, cyclopolydimethoxy Examples include cyclic polysiloxanes such as polysiloxane.

The reaction using a polysiloxane having more than one functional group (hereinafter referred to as a crosslinking polysiloxane) as a crosslinking agent can be carried out without a solvent or in the presence of a suitable organic solvent. , t using an organic solvent
These crosslinking reactions, which are preferably carried out in a six-liquid state, may be carried out in an appropriate manner depending on the type of component A, component B and crosslinking polysiloxane, reaction temperature, etc., but may be carried out in air, in the presence of moisture, or in an appropriate manner. The reaction may also be carried out in the presence of a catalyst. In addition, the amount of crosslinking agent polysiloxane used is component A.
The amount is preferably 0.7 to -2 parts by weight based on 7 parts of the adduct of component B.

Furthermore, the functional groups on the crosslinking polysiloxane may be different from each other as long as they are two or more, and the substitution positions of the functional groups are not particularly limited. It is preferable that they be located at separate locations such as at both ends. The functional group on such a crosslinking polysiloxane is limited to 1%, but may be limited to 1%, as long as it can undergo an addition or condensation reaction with the reactive group of the addition reaction product of component B to component A. Mention may be made of hydrolyzable atoms or m-groups on B.

The membrane dog material treated with the crosslinking agent as described above can be used as a reaction mixture, or after removing volatile components and other solvent-insoluble parts, it can be used as a solution in a suitable plated solvent for the addition reaction of component A and component B. As with other products, it can be rolled as is or made on a porous membrane.
I can do F.

The membrane of the present invention can be used with gases, especially oxygen, nitrogen, carbon oxide, hydrogen, helium, methane, alcohol.

It can be used to separate gas mixtures containing at least one of the following gases from each other.

Examples include the separation of nitrogen and oxygen in the production of oxygen-enriched gas, the separation of methane and helium in the recovery of helium from natural gas, and the separation of argon and hydrogen in the recovery of hydrogen from hydrogenation reaction exhaust gas. , Separation of methane heptahydrogen, nitrogen and hydrogen, recovery of hydrogen in cracking gas K , :i'') - Separation of carbon oxide and hydrogen, separation of carbon dioxide and nitrogen in the recovery of carbon dioxide from combustion gases It can be applied to etc.

Next, the present invention will be explained in detail with reference to Examples, but the content of the present invention is not limited to the Examples.

Reference example/ The air was replaced with dry nitrogen. Nippon Soda Co., Ltd. liquid rubber (N15so PB B-20θ0
゜Trademark) 6. tr 7 y was purchased and heated to 200°C.

Next, a mixture of triethoxysilane 371 and di-t-vapyl fluoride in a ratio of 0 to 1 was gradually added dropwise from the dropping funnel while stirring. After completing the dropwise addition for 3θ minutes, the flask f/ is heated to 20°C L/! Heating and stirring were continued for several hours. The reaction mixture was then treated under reduced pressure at room temperature to remove unreacted triethoxysilane and volatile components, yielding a yellow liquid of 10.73%. o, for the weight part! It can be seen that 6 weights of triethoxysilane was added. Dry toluene is added to the resulting addition and -2,? It was stored under a roof as a solution in parts by weight and used as a membrane forming solution for the following gas separation membrane.

The toluene solution of the triethoxysilane adduct obtained in Example/Reference Example/ was poured onto a glass plate to a thickness of 8,200 μm, and dried in the air at room temperature/overnight [dry to form a rubbery layer. A membrane was obtained.

The obtained membrane was mounted on a permeation test device, and the permeation characteristics of each depressant were measured as follows. In other words, the measuring device is an ultra-rather mixed device [manufactured by Amicon, Inc., USA]. After attaching the membrane ligature, apply the specified gas to the top m1 of the membrane in 7. Pressurize with θkKr/I gauge pressure, connect the bottom surface of the membrane to a gas buret, and then! ℃, the amount of gas permeating through the membrane over a certain period of time was measured, and the gas permeability was determined by measuring the amount of gas. The gas permeation rate of each l gas is expressed as R, and the unit is cc (8TP)/-・air・cm Hf
, and henceforth the units will be omitted. In addition, the selective separation of gases is expressed as a ratio of permeation rates.

The gas permeation performance of the membrane in this example is Ro, =’? , 3 X 10-” RN2 Seco, OX 10-Hatake Rot/RM2 = da, 2 Met.

Comparative Example/The gas permeation rate R of a commercially available Millipore filter (trade name) vSW'' (average porosity 0.0-21μ) was measured in the same manner as in Example/.The results are shown below.

RN2= /J X 1O-2 Ro□ = /, 7
,/RN2e O9riRaO2-=:=/ ,4' X
/ 0 "-" R002/RN t ;0Jl
(112-starvation λ×/θJ Ra!/RN, =ko,
A commercially available Millipore filter (product name) vswp (average pore size O6θ2!) was added to the toluene solution obtained in Example 3 and Reference Example/.
μ) was immersed under nitrogen for 2 minutes and then air-dried in the air to remove the molten t9. This pig was attached to the transmission test device 1# and the same procedure as in Example/ was carried out for each RO, = 3, 3 x /θ-'R
O2/RN2=ha/Roo2= /, g×/θ−'
Roo2/RN2=27. JRH2z/,ri×10
R)+2/RN2=2/JAs can be seen from the comparative example, there is selectivity for all of oxygen, carbon dioxide, and hydrogen with respect to nitrogen, but the selectivity for the element dioxide is particularly large.

) (Tomoyama Example 3 Reference example/The power obtained with triethoxylan, additives,
2. Toluene solution per ♂ weight 3. and 11α,ω-dihydroxydimethylpolysiloxane (Chisso SP Development Department P8
-/rij) θ, dibutyltin dilaurate as a reaction catalyst and 0. θj2 was stirred at room temperature in full air for 20 minutes to obtain uniform dissolution. Next, the obtained homogeneous solution was cast onto a glass plate at a temperature of /θθ0μ and left to dry overnight at room temperature. The obtained membrane was attached to a permeation test device, and the gas permeation rate R was measured in the same manner as in Example. The results are shown below, RN2=2. G×/θ−7 Ro, = / ,, 2 X 1O−6Ro2/Ry2
= s, θ Patent applicant Mitsubishi Chemical Industries, Ltd. Representative Patent attorney Hase - Others/names

Claims (3)

[Claims] (1) Structural unit 41 represented by the general formula for manure (in the formula, n is an integer from 0 or 1l-i/ to j). R1, Ht and R'3 are a hydrogen atom, a halogen atom, an alkyl group or a phenyl After adding a silicon compound having a hydrolyzable atom or atomic group to an ethylene polymer containing 1 mol% or more of ethylene-based polymers (which may be mutually the same or different), it is added as is or with a crosslinking agent. A gas separation membrane whose main component is a polymer material obtained from a treated body. (2) The hydrolyzable atom or atomic group is an amine group, an acyloxy group, an alkoxy group, a mercapto group, an acyl group, a cyan group, an epoxy group, a hydrogen atom, or a halogen atom. Gas separation membrane according to item 7. (3) The gas separation membrane according to item 7, wherein the crosslinking agent is a polysiloxane having two or more functional groups that can undergo an addition or condensation reaction with a hydrolyzable atom or atomic group.